How much deck mud do I need per square foot?

Deck mud is measured by volume, so it depends on the bed thickness. Multiply your area by the thickness in inches and divide by 12 to get cubic feet, then split that into sand and cement using a 5 to 1 ratio. Enter your numbers above for the full estimate.

What is the mix ratio for deck mud?

Deck mud, also called dry pack mortar, is commonly mixed at 5 parts sand to 1 part portland cement by volume. Some mixes use 4 to 1 for a richer blend, and shower pan mud sometimes includes a small amount of a latex or acrylic additive for strength.

How many bags of sand and cement do I need for deck mud?

Multiply your area by thickness in inches, divide by 12 to get cubic feet, then take 5/6 as sand volume and 1/6 as cement volume. Divide sand volume by the sand bag yield (about 0.5 cubic feet per 50 lb bag) and cement volume by the cement bag yield (about 1 cubic foot per 94 lb bag). Confirm the yields on the bags you actually buy.

Is deck mud the same as mortar?

Not quite. Deck mud is a dry pack mortar with a high sand to cement ratio (about 5 to 1) mixed just damp enough to hold a shape, used as a floor or shower pan bed. General purpose mortar for brick and block uses a lower ratio (around 3 to 1) and includes hydrated lime for workability, which is a different mix.

Deck Mud Calculator

This deck mud calculator estimates the volume of dry pack mortar (deck mud) needed for a tile or shower base from the area and bed thickness, and splits that volume into sand and portland cement using the standard 5 to 1 mix ratio. Enter your area and thickness to see the totals.

Deck mud, also called dry pack mortar or floor mud, is a stiff mix of sand and portland cement used for tile floors, shower pans and mortar beds. The volume needed comes from a simple area times thickness calculation, and the sand and cement split follows the standard 5 to 1 ratio by volume. This tool applies both formulas and reports the totals.

Area to cover(sq ft)Bed thickness (average)(in)

Total deck mud volume3.13 cu ft

Sand volume (5 parts): 2.6 cu ft
Portland cement volume (1 part): 0.52 cu ft
Sand bags at 0.5 cu ft / 50 lb bag: 6
Cement bags at 1.0 cu ft / 94 lb bag: 1

Bag counts use reference yields: confirm against the actual yield printed on the bags you buy. Add 10 to 15 percent for spillage and screeding waste.

What This Calculator Estimates

Total mortar volume in cubic feet, plus the sand and portland cement volumes at a 5 to 1 mix by volume. Bag counts are shown at a common bag yield, listed as a reference value that should be checked against the product you actually buy, since bag yields vary.

How to Use It

Enter the bed area in square feet and the bed thickness in inches. Typical shower pan beds run 1.25 to 1.5 inches minimum at the drain and slope up to the perimeter; typical floor mud beds run 3/4 to 1.25 inches. The tool gives you volume in cubic feet, plus sand and cement volumes at 5 to 1.

The Formula This Calculator Uses

Volume in cubic feet equals area in square feet times thickness in inches divided by 12. Deck mud is commonly mixed at 5 parts sand to 1 part portland cement by volume, so sand volume equals total volume times 5 divided by 6, and cement volume equals total volume divided by 6. Bag counts on this page use a reference bag yield of about 0.5 cubic feet per 50 lb bag of sand and about 1 cubic foot per 94 lb bag of portland cement, and should be confirmed against the actual bag yield printed on the product.

The 5 to 1 Mix Ratio and When It Changes

The 5 to 1 sand to cement ratio by volume is the standard reference for deck mud used under tile. Some installers work at 4 to 1 for a slightly richer, easier-to-pack mix, and some add a small dose of a latex additive or acrylic bonding agent for shower pans over waterproofing. The volume math does not change; only the split between sand and cement does. Confirm the ratio your product spec sheet or installer prefers before ordering.

Waste and Bag Rounding

Add 10 to 15 percent to the total volume for spillage and screeding waste, especially in shower pans where mud is packed to a slope. When ordering, round each bag count up to whole bags. The bag counts on this page are a first-order estimate; the exact number depends on the bag yield printed on your sand and cement, which can vary between suppliers.

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Frequently asked questions

How much deck mud do I need per square foot?: Deck mud is measured by volume, so it depends on the bed thickness. Multiply your area by the thickness in inches and divide by 12 to get cubic feet, then split that into sand and cement using a 5 to 1 ratio. Enter your numbers above for the full estimate.
What is the mix ratio for deck mud?: Deck mud, also called dry pack mortar, is commonly mixed at 5 parts sand to 1 part portland cement by volume. Some mixes use 4 to 1 for a richer blend, and shower pan mud sometimes includes a small amount of a latex or acrylic additive for strength.
How many bags of sand and cement do I need for deck mud?: Multiply your area by thickness in inches, divide by 12 to get cubic feet, then take 5/6 as sand volume and 1/6 as cement volume. Divide sand volume by the sand bag yield (about 0.5 cubic feet per 50 lb bag) and cement volume by the cement bag yield (about 1 cubic foot per 94 lb bag). Confirm the yields on the bags you actually buy.
Is deck mud the same as mortar?: Not quite. Deck mud is a dry pack mortar with a high sand to cement ratio (about 5 to 1) mixed just damp enough to hold a shape, used as a floor or shower pan bed. General purpose mortar for brick and block uses a lower ratio (around 3 to 1) and includes hydrated lime for workability, which is a different mix.